Node.js

Debug Commands

Debug Node.js applications with the built-in inspector, Chrome DevTools, and VS Code integration. Set breakpoints, inspect memory, and profile CPU usage.

12 commands

Pro Tips

Use 'node --inspect-brk app.js' to pause on the first line, then open chrome://inspect to connect.

Add 'debugger;' statements in code for programmatic breakpoints — works with any inspector client.

Use NODE_DEBUG=http,net to get verbose debug logging from Node.js core modules without code changes.

Common Mistakes

Never expose --inspect on 0.0.0.0 in production. The debug port allows arbitrary code execution.

Leaving debugger statements in production code causes the process to pause if an inspector connects.

Commands

Enable inspector

$ node --inspect app.js

Enable V8 inspector (default: localhost:9229).

Break on first line

$ node --inspect-brk app.js

Start inspector and pause before execution.

Wait for debugger

$ node --inspect-wait app.js

Wait for debugger before starting.

Debug module logs

$ NODE_DEBUG=http,net node app.js

Enable debug logs for core modules.

Trace warnings

$ node --trace-warnings app.js

Show stack traces for all warnings.

Trace deprecations

$ node --trace-deprecation app.js

Show stack traces for deprecations.

Remote debugging

$ node --inspect=0.0.0.0:9229 app.js

Enable inspector on all interfaces (remote access).

Built-in CLI debugger

$ node inspect app.js

Start built-in command-line debugger (95K+ searches).

Trace on exit

$ node --trace-exit app.js

Print stack trace when environment exits.

Throw on deprecation

$ node --throw-deprecation app.js

Throw errors on deprecated API usage.

Inspector over HTTP

$ node --inspect-publish-uid=http app.js

Publish inspector WebSocket URL over HTTP.

Abort on uncaught exception

$ node --abort-on-uncaught-exception app.js

Generate core dump on uncaught exceptions.